Abstract:

Objective To apply the human umbilical cord mesenchymal stem cells (hUCMSCs) labeled by Effectene mediated gadopentetate dimeglumine (Gd-DTPA) and to investigate the biologic characteristics of magnetically labeled stem cells and the rules of MRI of Gd-DTPA labeled MSCs in vitro. Methods The hUCMSCs was separated and purified by the tissue adherent method. The biological characteristics of cells in vitro were identified after being subcultured and amplified. The hUCMSCs was marked by Effectene transfected Gd-DTPA. The proliferation ability of Gd-DTPA labeled stem cells was detected by the counting method. Then stem cells were induced to differentiate to adipocytes and osteoblasts in vitro. The effects of Gd-DTPA on the biological characteristics of hUCMSCs were observed. The clinical 1.5T MRI system was used to observe changes of the signal intensity of Gd-DTPA labeled hUCMSCs with cell passages and explore the minimum cell mass of MRI. Results Primary cells were obtained by applying the tissue adherent method for two weeks. The cells were fusiform with whirlpool-like growth. After two passages, cells were morphologically homogeneous. The flow cytometry detected that the third passage cells had high expressions of CD29, CD44, CD90, and CD105 and no expression of CD31, CD40, CD45, and HLA-DR. The cells could be induced to adipocytes and osteoblasts in vitro. Effectene could successfully transfected with Gd-DTPA into stem cells. The proliferation of labeled stem cells was not affected and the cells could be induced to differentiate towards osteoblast or adipocyte in vitro. The results of MRI scanning of Gd-DTPA labeled stem cells showed high signal on T1WI and the continuous tracing lasted about 12 d in vitro. Conclusion The tissue adherent method can effectively isolate and purify hUCMSCs. It is feasible to perform MRI tracking in vitro through hUCMSCs labeled by Effectene transfected Gd-DTPA.

Key words: mesenchymal stem cells, magnetic resonance imaging, gadopentetic acid dimeglumine, tracking